(1) Field of the Invention
The invention relates to a method of metallization of an integrated circuit device, and more particularly, to a metallization method with good step coverage in the manufacture of an integrated circuit device.
(2) Description of the Prior Art
In the fabrication of integrated circuit devices, metal layers make contact to lower conductive layers of the integrated circuit through vias in an insulating layer. Aluminum is often used as the interconnection metal. However, the sputtering process used to apply the aluminum often results in incomplete filling of the via openings. Large aluminum grains tend to form on the surface of the insulating layer within the via openings, causing voids.
Differing temperatures and deposition rates have been used to try to overcome the problem of voids. U.S. Pat. Nos. 4,994,162 to Armstrong et al and 5,108,951 to Chen et al describe such methods.